These star tables
and some of the comments were sent to us by Gerald Nordley,
science
fiction writer, member of the CONTACT group, and a very good
friend to world builders! Thank you very much for your help,
Mr Nordley!

The stars in these tables are arranged in
the classes used in the Main Sequence.
Choose your star from these tables and you will have some of
the numbers that you need for your solar system and your planet.

Our sun is a G2 star. As we found out from
our hands-on activity, our sun formed
4.5 billion years ago. Earth also formed about 4.5 billion years
ago, and 3.2 billion years ago, or perhaps even earlier, the
first single celled life forms appeared. When you consider that
the earth had to cool from a molten state first, life seems to
have appeared quite quickly. However, the jump to multicellular
life forms took a long time. Multicellular life forms began
to develop only 600 million years. If you want to have live forms
that you can actually see, you need to choose a star with a long
enough life time.

You should choose your star type from these
tables. Write down the information about that star's row, with
the headings.

Stellar magnitude over all wavelengths as
seen from ten Parsecs 32.6 Light years). At that distance,
the sun would appear to be a 4th magnitude star (4.75 to be precise).

Stars are different sizes, and some are much
brighter than others. Astronomers classify stars by brightness.
This is difficult because some stars are relatively close to
us, while others are very far away. This measurement tells us
how bright the different stars are when viewed from the same
distance (but not the same place).

Bolometric Luminosity: a star's power output over all wavelengths
(Sol = 1)

This includes light, heat,
ultraviolet radiation, infrared radiation, gamma rays, and so
on. Many wavelengths of the energy that stars radiate cannot
be detected by our senses, but only with special instruments.

Bolometric Luminosity is the
total energy put out by a star spread over all wavelengths. Use
it for calculating the total energy balance and average effective
temperature for a planet.

This is probably best for
photosynthesis as well, however, for planets with deep atmospheres
around very red stars, one might want to research atmospheric
absorption as a function of wavelength and see how that compares
to the stars blackbody spectrum. For planets with thick atmospheres
or enhanced ozone layers around stars hotter than the sun, use
visual luminosity for photosynthesis, as atmospheres attenuate
ultraviolet light much more than visual.

L
Zams:

Zero Age luminosity; bolometric luminosity
after the star's
initial contraction; this is problematical for late M stars
and below, which contract essentially forever.

Visual Luminosity:

in terms of Sol at the same distance. For
hotter or cooler stars this is less than L bol, because much
of those star's radiation is in the invisible ultraviolet (very
hot) or infrared (warm) part of the spectrum. If one was close
enough to a red dwarf that it appeared as bright as the sun,
one would get about 100 times less ultraviolet intensity.

If you look at these tables you will see interesting
changes as the stars get smaller. Pay special attention to the
colored sections of the tables, as you will be using these numbers
in planning your own solar system.

O Class Stars -- Very Large, Very Hot, Very Fast
Burning

Class

Temperature in degrees Kelvin

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass
(Mass of our sun = 1)

Radius

Terrestrial Equivalent Orbit
in AUs

Lifetime
in billions of years

04

48000

-10.24

990000.00

980000.00

1.75E4

90.000

14.400

995.00

.002

05

44500

-9.99

790000.00

560000.00

1.46E4

60.000

15.000

889.00

.004

06

41000

-9.31

420000.00

238000.00

1.20E4

37.000

12.900

648.00

.005

07

38000

-8.79

260000.00

140000.00

9350.00

30.000

11.800

510.00

.006

08

35800

-8.33

170000.00

84500.00

6960.00

23.000

10.800

412.00

.008

09

33000

-7.72

97000.00

62700.00

4820.00

23.300

9.560

311.00

.009

B Class Stars -- Hot and Fast Burning

Class

Temp/K

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass (Mass
of our sun = 1)

Radius

Terrestrial
Equivalent Orbit
in AUs

Lifetime in billions
of years

B0

30000

-7.04

52000.00

40800.00

3020.00

17.500

8.470

228.00

.010

B1

25400

-5.76

16000.00

18800.00

1420.00

14.200

6.560

126.00

.013

B2

22000

-4.64

5700.00

9720.00

698.00

10.900

5.220

75.50

.020

B3

18700

-3.45

1900.00

3150.00

339.00

7.600

4.170

43.60

.043

B5

15400

-2.55

830.00

1500.00

231.00

5.900

4.060

28.80

.066

B6

14000

-2.00

500.00

823.00

175.00

5.200

3.810

22.40

.075

B7

13000

-1.51

320.00

496.00

133.00

4.500

3.540

17.90

.198

B8

11900

-.89

180.00

308.00

91.90

3.800

3.170

13.40

.367

B9

10500

-.19

95.00

187.00

63.30

3.350

2.960

9.75

.475

A Class Stars -- Do Not Last Long Enough to Support
Complex Life Forms

Class

Temperature in degrees Kelvin

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass (Mass
of our sun = 1)

Radius

Terrestrial Equivalent
Orbit
in AUs

Lifetime in billions
of years

A0

9520

.42

54.00

87.20

43.70

2.900

2.710

7.35

.583

A1

9230

.89

35.00

76.60

30.20

2.720

2.320

5.92

.627

A2

8970

1.21

26.00

66.10

23.10

2.540

2.120

5.10

.670

A3

8720

1.44

21.00

55.60

19.20

2.360

2.010

4.58

.713

A5

8200

1.88

14.00

34.60

13.00

2.000

1.860

3.74

.800

A7

7850

2.20

10.50

25.30

10.00

1.840

1.760

3.24

1.120

A8

7580

2.41

8.60

20.60

8.37

1.760

1.710

2.93

1.280

Class F Stars: Some of These Might Have Life-Bearing
Planets

Class

Temperature in degrees Kelvin

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass (Mass
of our sun = 1)

Radius

Terrestrial Equivalent
Orbit
in AUs

Lifetime in billions
of years

F0

7200

2.72

6.50

11.20

6.38

1.600

1.640

2.55

1.600

F2

6890

3.17

4.30

6.57

4.14

1.520

1.460

2.07

1.760

F5

6440

3.49

3.20

4.47

3.00

1.400

1.440

1.79

3.440

F8

6200

3.94

2.10

2.51

1.93

1.190

1.260

1.45

6.880

G Class Stars: Possible Suns for Planets with Life:
The Sun is a G2 Star

Below: The
E0 Class contains the the lowest mass Main Sequence
stars.
Stars less massive than class E0 are called Brown Dwarfs.

Small, Heat-Radiating Bodies Less Than a Tenth
the Mass of Our Sun

Class

Temperature in degrees Kelvin

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass (Mass of our sun
= 1)

Radius

Terrestrial Equivalent Orbit
in AUs

E0

1800

15.74

40.00E-6

NA

277.0E-9

.080

.065

6.3E-3

E2

1600

16.06

30.00E-6

NA

4.2E-9

.072

.072

5.5E-3

E4

1300

16.74

16.O0E-6

NA

1.0E-9

.064

.079

4.0E-3

E6

1000

17.25

10.00E-6

NA

--

.053

.106

3.7E-3

E8

800

18.00

5.00E-6

NA

Too

.040

.117

2.2E-3

Below:
MJ means Jupiter masses, each about 1/1000 the mass of the sun.
The Brown Dwarf/Jovian Transition is between E8 and J0

Astronomical Bodies Smaller than Mass of Jupiter:
Radiate Heat

Class

Temperature in degrees Kelvin

Bolometric Absolute Magnitude

Bolometric Luminosity

L Zams

Visual Luminosity

Mass (Compared
to mass of Jupiter (.001 of our sun))

Radius

Terrestrial Equivalent
Orbit
in AUs

J0

700

18.56

3.00E-6

NA

dim

MJ .118

.118

1.7E-3

J2

600

19.31

1.50E-6

NA

to

MJ .114

.114

1.2E-3

J4

400

21.06

.30E-6

NA

see

MJ .114

.114

.5E-3

J7

100

27.25

1.00E-9

NA

with

MJ .106

.106

Below

J8

80

29.11

.18E-9

NA

human

MJ .070

.070

surface

J9

50

32.56

7.50E-12

NA

eyes

MJ .037

.037

Below

Non-
Luminous

30

34.75

1.00E-12

NA

--

MJ .037

.037

surface

The bottom end of the Jovian scale consists of Jupiter,
Saturn
Neptune and Uranus in that order, with effective temperatures
from Lang, adjusted for solar heating and known radius values
Jupiter is a J7.